The present invention relates to gas turbine engines. In particular, the invention relates to air exit port containment systems for air turbine starters.
Gas turbine engines require a starter component to rotate the core of the gas turbine to provide sufficient speed and compression to facilitate igniting the engine. An air turbine starter (ATS) is commonly employed in such applications. The ATS is powered by compressed air from an external source. The compressed air passes over blades of an air turbine in the ATS and exits the ATS through an air exit port. As the air turbine rotates, it rotates a shaft connected to the compressor in the gas turbine engine, providing sufficient torque to start the engine.
As with any powerful, high speed rotary system, such as an ATS, there is a risk that internal failure of a component, such as an air turbine, can result in high energy fragments escaping the rotary system and damaging nearby systems. Primary containment systems are employed in positions directly radially outward of rotating components, such as air turbine blades, to prevent large fragments from escaping the system. In the case of an ATS, with its large flow path and volume of compressed air moving past the air turbine blades, it is also possible for midsize and smaller fragments to be carried out of the ATS through an air exit port with sufficient energy to damage nearby components. For example, aircraft often have an ATS physically attached to each engine and proximate fuel pumps, fuel lines, and other important systems. Fragments escaping the ATS through the air exit port have the potential to damage such systems. Generally, an ATS will have a separate containment system, such as a baffle system, positioned at the ATS air exit port to contain such fragments within the ATS or, at least absorb and reduce the kinetic energy of any fragments that do escape through the air exit port.